How to replace a light switch (2023)

Light switches are functional, yes, but they can look fabulous – you’d be surprised how powerful a full switch and socket replacement project can be in terms of adding final flourishes that lift every room. You can also add nifty functionality too, like motion detecting.

If you’re a home renovator, to pay an electrician to replace every light switch in your home would cost you a bomb. It’s a simple enough job to do yourself if you have the correct tools and you know how to safely isolate your lighting circuit(s). This guide will tell you all you need to know to replace either a broken light switch or change up its look.

Do I need to know how to replace a broken light switch, or do I need to change the light bulb?

It might seem like a silly question, but sometimes people forget to change the light bulb. So, before you go delving into potentially dangerous electrical circuits, try replacing the light bulb. Our How to change a light bulb article will help here. Our How to fix a light switch article also has some great troubleshooting information.

Safety first
It’s vital to be safe around electricity. You must make sure that you isolate the circuit you’re working with correctly and that you triple-check the circuit is dead before you attempt the replacement.

If you don’t know what you’re doing, there’s no question that you should get a qualified electrician to do this task. Accidents with mains voltage electricity can be deadly so it’s not worth taking any amount of risk.

Safe electrical isolation procedures
1. If your house is wired correctly (you’ll be surprised how many houses aren’t), the lighting circuitry should all be isolated from a single point.

2. A good way to test this while the lights are on is to go to your fuse box or consumer unit and switch off the circuit breaker on the ‘lighting’, or ‘downstairs lighting’ – or whichever circuit you’re going to be working on. This will cut the electricity supply, either to just the downstairs lighting, for example, or to all the lighting in your house.

3. If you can see that your lights have all now switched off, this is an indication that you have isolated the circuit.

4. Now test the lighting with an approved voltage tester – this will tell you for sure if the lighting circuit you want to work is dead and safe to work on.

5. Of course, if you want to be 1000% sure, you can switch off the big red circuit breaker, which cuts the mains electricity supply to your whole house. This may inconvenience the rest of your household, however, and will have to reset all your clocks when you switch back on.

Before we remove your old light switch, let’s talk about what type of light switch you’re replacing, and the types of light switches you can potentially upgrade to.

Different types of light switches

Wall-mounted light switches fittings can contain one, two, three or even more individual switches or ‘gangs’ that allow you to switch on and off different light fittings in a larger room or area from one switch.

What does ‘1’ and ‘2’ mean on the back of a light switch faceplate?
The 1 and 2 are the gangs mentioned above. A simple light switch with only 1 button on it is called a ‘1 gang switch’, meaning it controls only a single lighting function. A ‘2 gang’ has two buttons and controls 2 lighting functions, and so on.

What light switch do I need?
You’ll need different light switches in different areas of your house. 1 gang switches will be fine for most functions, but there are other options to keep in mind. For example, a dimmer switch in your lounge may be perfect for weekend movie nights. Have a look online at the available switches, and then think about the potential functions you could have in your home.

Light switch functions and finishes

From functional white plastic to stylish metallic finishes, there’s a plethora of options available. Dimmers let you raise and lower the light level – and may have a combined or separate on/ off and dimming control, so you don’t have to readjust the light level every time you turn on the light. They’re wired just like a standard switch.

What types of light switches can I have in the bathroom?
Because electricity and water can be a deadly combination, only ceiling-mounted pull-cord switches are permitted to be installed in bathrooms and/ or shower rooms, as per UK building regulations.

How to replace a broken light switch

Let’s start with the basic how-to guide for replacing a broken light switch. This also includes how to replace a light switch like for like – eg. plastic for plastic or metal for metal.

Tools you’ll need:

• Small screwdriver
• Approved voltage tester
• Your smartphone to take photos of the wiring

Warning: If you’re switching from a plastic light switch faceplate to a metal faceplate, you must follow the specific steps in the section titled ‘Safety first – earthing metal light switches’.

How do I know my light switch is faulty?

If your light switch doesn’t turn on or off, no matter how many times you flick it on or off or turn the dimmer switch, or you notice that the toggle or switch head moves or doesn’t stay in its place, it’s pretty clear the switch is faulty and needs to be replaced.

How to replace a simple light switch
This is a simple task – just follow the step-by-step instructions:
1. Isolate the lighting circuit you’ll be working on using the safety procedures above.

2. Test that the lighting circuit is dead with an approved voltage tester.

3. Remove the light switch faceplate from the wall and take a picture of the wiring for when you reattach the new one.

4. Keep hold of your original screws as you may have to re-use them. This is because modern fittings come with metric-sized screws and older fittings might have imperial threads.

5. Unscrew the small screws from the back of the light switch to release the wires.

6. Take your new light switch and reverse your previous steps to reattach the wires in the same configuration as the photo you took.

7. Tighten the small screws and reattach to the wall.

8. Flick the circuit back on at the circuit breaker and test your new light switch.

Safety first – earthing metal light switches
If you’re switching from a plastic to a metal light switch faceplate, it’s very important to ‘earth’ your new metal faceplate to protect you and your family from electrocution, should the light switch ever develop a fault, eg. a piece of wiring comes loose and touches the metal faceplate.

What is earthing?

If there’s a fault in any electrical installation, including a loose wire in a light switch, you could get an electric shock if you touch a live metal part. This is because the electricity may use your body as a path from the live part to the earth.

Basically, electricity is negatively charged and it’s attracted to the ground because the earth is positively charged. It will always find the quickest path to the ground.

‘Earthing’ is done by electricians to protect you from an electric shock, by providing a path (a protective conductor) for a fault current to flow to earth. It also causes the protective device (either your circuit-breaker or fuse) to switch off the electric current to the circuit that has the fault.

For example, if there’s a problem with your light switch, the fault current flows to earth through the protective (earthing) conductors. Your protective fuse or circuit-breaker also switches off the electrical supply to the light switch – known as ‘tripping’ the switch. The light switch is now safe from electrocuting anyone who touches it – you must investigate the reason for the tripped switch immediately.

How to earth a metal light switch

The most common light switch combination is a metal mounting box or ‘back box’ inside the wall connected to a plastic faceplate. In this case, the earth core or cores must be connected to the earthing terminal of the back box. If this is your current set-up and you plan to keep a plastic faceplate, you don’t need to do anything.

If, however, you’re switching to a metal faceplate – which has been a big trend in the last few years – you must run the main earth core to the faceplate, not the back box.

Warning: It was common practice years ago not to include the earth wire in lighting circuits. So, if you follow the next few steps and find there’s no earth wire, then you can’t fit a metal light switch as it would be extremely dangerous.

Here’s what to do (providing there’s an earth wire):

1. Isolate the circuit or cut the mains electricity supply to the whole house (follow the safety procedure outlined above).

2. Test the circuit is dead with an approved voltage tester.

3. Now unscrew your plastic switch and pull it forwards (keep the screws)

4. You’ll probably see that there are two wires going into your plastic switch – take a photo of which wire goes into which terminal.

5. Look at your metal back box inside the wall. You’ll see a green and yellow earth wire connected to the back box.

6. Again, if there is no earth wire present, stop what you’re doing and replace your current switch. You will need to get in touch with a professional electrician.

7. If you can see the main earth core connected to your back box, you can go ahead and unscrew the wires connected to the terminals in your old switch faceplate and pull the cores from the terminals.

8. Now unscrew and remove your main earth core from the back box terminal.

9. Attach the earth core to your metal faceplate earth terminal.

10. You’ll now need to attach the other two wires to the correct terminals (check your photo of the old set-up to do this).

11. You can now run a short length of green and yellow earth wiring back from the earthing terminal on your new metal faceplate to the back box earth terminal. This is called a supplementary earth and considered good practice by most electricians as the function of this is to provide an earthed path from the faceplate to the back box – this is done already by the metal screws you use to fix the metal faceplate to the wall. But it’s still considered good practice by most electricians.

How to replace a light switch with a motion sensor

If you just want to fix a broken light switch, you’ll find some good troubleshooting information in our How to fix a light switch article.

Motion sensor switches, on the other hand, are more advanced light switches used more often in offices and warehouses. A motion sensor switch will automatically turn on the lights whenever it detects motion and can certainly be handy in a home – for example, when you walk into the garage carrying something heavy, or a dark utility room with armfuls of laundry.

If a motion sensor switch sounds very useful for your home, the first thing you need to do is check you have the right wiring. Namely, you need a neutral wire, because most motion sensing switches require a neutral wire attached to them.

Before you buy a motion sensor switch:
Before you go shopping for a motion sensor switch, you should check for two things:

1. Do you have a neutral wire available in the back box? Isolate the circuit or turn off your mains electricity at the red switch in your consumer unit. A neutral wire is a blue wire (or if you have older wiring, a black wire) that will most probably not be connected to the terminal. Please bear in mind that your wiring may not be correctly colour coded, so carefully check the wires and terminals they’re connected to on the current faceplate and back box and make sure you’re certain which wires are which before doing anything else.

If there’s a neutral wire, hooray! You can go out and buy a motion sensor switch and fit it using the following step-by-step guide. If not, you must make sure that the switch you buy doesn’t require a neutral. If this isn’t possible, a motion sensor won’t be feasible for you unless you have your electrics rewired by a professional.

2. You need to know what type of switch you currently have. Is it a 1 gang, a 2-way switch, or 3-way switch? You’ll need to match the new motion sensor switch with your old switch for it to be wired correctly and safely.

How to install a motion sensor switch (providing you have an available neutral wire)

Please note: follow the motion sensor switch installation instructions exactly. Our guide should only be used as a back-up reference.

1. Isolate the circuit using the safety procedures above.

2. Test the circuit is dead.

3. Unscrew your current switch from the wall and pull it away from the back box so you can see the wires.

4. Look for a blue or black wire that doesn’t connect to your current faceplate. This is your neutral wire.

5. Now you can fit the switch as per all other methods above. Take a photo of the current wires and connections, then unscrew the wires from the terminals and remove the old faceplate.

6. Connect the correct wires to the correct terminals in accordance with your motion sensor switch instructions, making sure to connect the neutral properly.

7. Follow your new switch instructions to make sure you have followed the correct earthing procedures. Remember, if the faceplate is metal, it’ll need to be earthed first and it’s good practice to fit a supplementary earth wire back to the back box.

8. Screw your new faceplate to the wall, reconnect the power and test your new light’s capabilities.

Make sure you’re never left in the dark

When lighting, sockets and fuse boxes unexpectedly break down, they can bring a busy household to a grinding halt. We provide Electrical Emergency and Breakdown cover for your wiring, broken sockets and any fuse box breakdowns that might occur. With protection in place our Home Experts will help make sure that unexpected electrical problems don’t leave you eating dinner in the dark.

FAQs

Do I need an electrician to replace a light switch?

No. If you’re replacing a broken light switch or a like-for-like one, it’s a simple task that only requires you to know how to safely isolate the circuit and some basic tools. If you’re renovating your home and switching to metal faceplates, you’ll need to earth your new faceplate which requires more skill, but if you’re a competent DIYer, it’s a pretty simple job.

How much does it cost to replace a light switch?

In the UK if you pay an electrician to replace a broken light switch, you can expect to pay around £35-£55. However, if the job is more complicated – with faulty wiring or rewiring involved, you could be looking at double or triple that amount.

How long does it take to change a light switch?

If you’re simply replacing a broken light switch like for like, it shouldn’t take longer than 30 minutes, providing you’ve got the correct replacement switch, the right tools and you follow the correct electrical safety procedures.

Can you replace a light switch without turning off the power?

No, it’s extremely dangerous to work on any electrical lighting, wiring, sockets or appliances without first isolating the circuit you’re working on. If you’re in any doubt about electrical safety, call a professional electrician.